<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8" />
		<title></title>
	</head>
	<body>
		<canvas id="canvas" style="border: 1px solid red;"></canvas>
		<script type="text/javascript">
			var canvas = document.getElementById('canvas')
			var cxt = canvas.getContext('2d')
			canvas.width = 550
			canvas.height = 400
			var linJoin = ['miter', 'round','bevel']
			
			cxt.lineWidth = 10
			for(var i = 0; i < linJoin.length; i++){
				cxt.lineWidth = 15
				cxt.lineJoin = linJoin[i]
				cxt.beginPath()
				cxt.moveTo(-5, 5+i*40)
				cxt.lineTo(35, 45+i*40)
				cxt.lineTo(75, 5+i*40)
				cxt.lineTo(115, 45+i*40)
				cxt.lineTo(155, 5+i*40)
				cxt.stroke()
			}
		</script>
	</body>
</html>
